import java.util.Scanner;

public class demo1 {
    public static void main(String[] args) {
        double r=4;
      yuan(r);
    }
    public static void yuan(double r){
        double pi=Math.PI;
        double S=pi*r*r;
        double H=2*pi*r;
        System.out.println("圆的面积为:"+S);
        System.out.println("圆的周长为:"+H);
    }
}
